Conventionally, bathroom faucet is coupled with rotational switch for users to use, and most rotational switches have one bulky cylindrical knob with shallow slots on the outer surface for the user to hold. When in use, the user holds and covers the knob with the fingers, and then rotates the knob to switch water on and off. However, when the rotational switch is not in use for a long period of time, it becomes tight due to filthy substances in the water and degraded parts of the switch. Under this situation, it is even more difficult for the elderly and children who do not have enough strength in their hands. Moreover, since the knob is a bulky and cylindrical, it is difficult to know the current state of the water, especially the temperature and amount of the water. If the user can not precisely control the temperature and the amount of water, the user may either be burned by hot water or experience cold water. These are disadvantages of conventional bathroom faucet with rotational switch.